Display device, control method for display device, and program

ABSTRACT

A specific posture is set as a standard posture of the head of a user wearing a display device, and a movementfrom the standard posture is detected. The detected movement of the head is associated in advance with a first mode and a second mode that are display modes of the image display unit, and the image display unit performs display in the first mode when the detected movement of the head is a movement in a predetermined first direction and exceeds a predetermined first threshold value and performs display in the second mode when the movement is a movement in a second direction that is different from the first direction and exceeds a predetermined second threshold value. An input is received in an input mode associated in advance with the first mode or the second mode.

The present application is based on, and claims priority from JPApplication Serial Number 2020-013124, filed Jan. 30, 2020, thedisclosure of which is hereby incorporated by reference herein in itsentirety.

BACKGROUND 1. Technical Field

The present disclosure relates to a display device and a control methodfor the display device.

2. Related Art

A head-mounted display device that is worn on the head of a user,transmits an outside scene such that it is able to be visuallyrecognized, and also allows various displays to be superimposed on theoutside scene has been proposed. Such a display device can be set, forexample, to display an instruction manual for a work target whileallowing the user to view the work target as necessary or to display apart of a display image of an information processing device such as acomputer. JP-A-2018-101019 has been disclosed as an example of theformer, JP-A-2019-036914 has been disclosed as an example of the latter,and the like. With such a display device, coordination between theinformation processing device and the display device, improvement inwork efficiency, and the like can be achieved.

However, with respect to such a display device, while it is possible todisplay a variety of information in various modes, a relationshipbetween input operations and display modes, such as performing a scrolloperation for displayed information, or applying various settings hasnot been sufficiently taken into account. For example, inJP-A-2019-036914, while a part of a display screen on the informationprocessing device side is displayed on a head-mounted display device,operations such as an operation of switching display, an operation ofselecting an option, and the like must be made on the informationprocessing device side, and the information to be displayed has nothingto do with the input mode, which makes the systems difficult to use.

SUMMARY

The present disclosure can be implemented as a head-mounted displaydevice configured to cause outside scenes to be visually recognized. Adisplay device includes an image display unit configured to display animage, an input unit coupled to the display unit and configured toaccept input in at least a plurality of input modes, a setting unitconfigured to set, as a standard posture, a specific posture of the headof a user wearing the display device, a detection unit configured todetect a movement of the head of the user wearing the display devicefrom the standard posture, a display control unit configured toassociate a movement of the head with a first mode and a second modethat is different from the first mode, that are display modes of theimage display unit, and cause the image display unit to perform displayin the first mode when the detected movement of the head is a movementin a predetermined first direction and exceeds a predetermined firstthreshold value and perform display in the second mode when the movementis a movement in a second direction that is different from the firstdirection and exceeds a predetermined second threshold, and an inputcontrol unit configured to cause the input unit to accept the input inan input mode associated in advance with the first mode or the secondmode of the image display unit among the plurality of input modes whenthe image display unit performs display in the first mode or the secondmode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory view illustrating an external configuration ofan HMD according to an embodiment.

FIG. 2 is a plan view illustrating a configuration of a main part of anoptical system included in an image display unit.

FIG. 3 is a schematic configuration diagram illustrating a configurationof a signal processing circuit of the display device.

FIG. 4 is a flowchart showing a display processing routine executed by acontrol device in a first embodiment.

FIG. 5 is an explanatory diagram illustrating virtual display in theimage display unit.

FIG. 6 is a flowchart showing a display process under each condition.

FIG. 7 is a flowchart showing a right side and left-side displayprocessing routine in the display process.

FIG. 8 is an explanatory diagram illustrating an example of display onright and left sides.

FIG. 9 is a flowchart showing a lower side display processing routine inthe display process.

FIG. 10 is an explanatory diagram illustrating an example of lower sidedisplay.

FIG. 11 is an explanatory diagram illustrating another example of thelower side display.

FIG. 12 is a flowchart showing a display processing routine according toa second embodiment.

FIG. 13 is a flowchart showing a display process under each condition.

FIG. 14A is an explanatory diagram illustrating an example of display ina second display unit of a control device.

FIG. 14B is an explanatory diagram illustrating another example ofdisplay in the second display unit of the control device.

FIG. 14C is an explanatory diagram illustrating another example ofdisplay in the second display unit of the control device.

FIG. 14D is an explanatory diagram illustrating another example ofdisplay in the second display unit of the control device.

FIG. 14E is an explanatory diagram illustrating another example ofdisplay in the second display unit of the control device.

DESCRIPTION OF EXEMPLARY EMBODIMENTS A. First Embodiment

A-1. Overall Configuration of HMD:

FIG. 1 is a diagram illustrating an appearance configuration of ahead-mounted display (HMD) 100 as a display device according to anembodiment of the present disclosure. The HMD 100 is a display deviceincluding an image display unit 20 configured to enable a user wearingit around his or her head to visually recognize virtual images and acontrol device 70 configured to control the image display unit 20. Thecontrol device 70 is a device configured to perform processing necessaryto exchange signals with the image display unit 20 to cause the imagedisplay unit 20 to display images, and includes a display 73 having atouch panel function. The HMD 100 has two display units, and thus whenthere is a need to distinguish the two units from each other, the imagedisplay unit 20 may be referred to as a first display unit and thedisplay 73 as a second display unit.

The control device 70 serves as an input unit, an input control unit, asetting unit, and a display control unit as will be described below. Inthe HMD 100, the control device 70 receives a video (including audio)transmitted from a mobile terminal 110, such as a smartphone, andoutputs the video to the image display unit 20 in wirelesscommunication, to cause the image display unit 20 to display the image(including the moving image) and play back the audio.

The image display unit 20 is a wearable body to be worn around the headof a user and has an eyeglasses shape in this embodiment. The imagedisplay unit 20 includes a main body including a right holding part 21,a left holding part 23, and a front frame 27, and includes a rightdisplay unit 22, a left display unit 24, a right light-guiding plate 26,and a left light-guiding plate 28 in the main body.

The right holding part 21 and the left holding part 23 respectivelyextend rearward from both ends of the front frame 27 to hold the imagedisplay unit 20 on the head of the user, like the temples of eyeglasses.Here, one of the ends of the front frame 27 located on the right side ofthe user wearing the image display unit 20 is referred to as an end ER,and the other end located on the left side of the user is referred to asan end EL. The right holding part 21 is provided to extend from the endER of the front frame 27 to a position corresponding to the right headof the user wearing the image display unit 20. The left holding part 23is provided to extend from the end EL of the front frame 27 to aposition corresponding to the left head of the user wearing the imagedisplay unit 20.

The right light-guiding plate 26 and the left light-guiding plate 28 areprovided in the front frame 27. The right light-guiding plate 26 ispositioned in front of the right eye of the user wearing the imagedisplay unit 20 to allow the right eye to visually recognize an image.The left light-guiding plate 28 is positioned in front of the left eyeof the user wearing the image display unit 20 to allow the left eye tovisually recognize an image.

The front frame 27 has a shape in which an end of the rightlight-guiding plate 26 is connected to an end of the left light-guidingplate 28. The position of the connection corresponds to a positionbetween the eyebrows of the user wearing the image display unit 20. Thefront frame 27 may include a nose pad part that comes in contact withthe nose of the user wearing the image display unit 20, the nose padpart being provided at the position of the connection of the rightlight-guiding plate 26 and the left light-guiding plate 28. In thiscase, the nose pad part, the right holding part 21, and the left holdingpart 23 allow the image display unit 20 to be held around the head ofthe user. In addition, a belt that brings the right holding part 21 andthe left holding part 23 in contact with the back of the head of theuser wearing the image display unit 20 may also be connected to theright holding part 21 and the left holding part 23. In this case, thebelt enables the image display unit 20 to be firmly held around the headof the user.

The right display unit 22 displays images on the right light-guidingplate 26. The right display unit 22 is provided on the right holdingpart 21 and is positioned adjacent to the right head of the user wearingthe image display unit 20. The left display unit 24 displays images onthe left light-guiding plate 28. The left display unit 24 is provided onthe left holding part 23 and is positioned adjacent to the left head ofthe user wearing the image display unit 20.

The right light-guiding plate 26 and the left light-guiding plate 28according to this embodiment are optical parts (e.g., prisms orhologram) formed of an optical transparent resin or the like, and guideimaging light output by the right display unit 22 and the left displayunit 24 to the eyes of the user. Note that surfaces of the rightlight-guiding plate 26 and the left light-guiding plate 28 may beprovided with light control plates. The light control plates are thinplate-like optical elements having varying transmittance depending on awavelength region of light, and function as so-called wavelengthfilters. The light control plates are arranged to cover a surface of thefront frame 27 (the surface opposite to the surface facing the eyes ofthe user), for example. Appropriate selection of optical properties ofthe light control plates allows the transmittance of light in anywavelength region, such as visible light, infrared light, andultraviolet light to be adjusted, and allows an amount of outside lightincident on the right light-guiding plate 26 and the left light-guidingplate 28 from outside and passing through the right light-guiding plate26 and the left light-guiding plate 28 to be adjusted.

The image display unit 20 guides imaging light generated by the rightdisplay unit 22 and the left display unit 24 to the right light-guidingplate 26 and the left light-guiding plate 28, respectively, and to allowthe user to visually recognize a virtual image with the imaging light(which will also be referred to as “displaying an image”). When theoutside light traveling from in front of the user passes through theright light-guiding plate 26 and the left light-guiding plate 28 and isincident on the eyes of the user, the imaging light forming a virtualimage and the outside light are incident on the eyes of the user. Thus,the visibility of virtual images viewed by the user can be affected bythe intensity of the outside light.

Thus, the ease of visual recognition of virtual images can be adjusted,for example, by mounting the light control plates on the front frame 27and appropriately selecting or adjusting the optical properties of thelight control plates. In a typical example, light control plates havingoptical transparency to the extent that a user wearing the HMD 100 canvisually recognize at least an outside scene may be selected. The use ofthe light control plates is expected to be effective for protecting theright light-guiding plate 26 and the left light-guiding plate 28 andpreventing damage to the right light-guiding plate 26 and the leftlight-guiding plate 28, adhesion of dust, and the like. The lightcontrol plates may be detachable from the front frame 27 or each of theright light-guiding plate 26 and the left light-guiding plate 28.Alternatively, a plurality of different types of light control platesmay be provided to be detachable for replacement, or the light controlplates may be omitted.

In addition to the above-described members for image display, the imagedisplay unit 20 is provided with video cameras 61R and 61L, aninward-facing camera 62, an illuminance sensor 65, a six-axis sensor 66,and an indicator 67. The two video cameras 61R and 61L are arranged onthe front frame 27 of the image display unit 20. The two video cameras61R and 61L are provided at positions approximately corresponding to theeyes of a user, and are designed to be able to measure the distance to atarget object in so-called binocular vision. The distance is measured bythe control device 70. Note that the video cameras 61R and 61L may beprovided at any position as long as a distance can be measured in abinocular vision, or may be disposed at the ends ER and EL of the frontframe 27. Note that a distance to a target object can be measured usinga configuration implemented by the analysis of a monocular camera and animage of the camera, a configuration implemented by a millimeter waveradar, or the like.

The video cameras 61R and 61L are digital cameras including an imagingelement such as a CCD or a CMOS, an imaging lens, and the like. Thevideo cameras 61R and 61L capture an image of at least part of anoutside scene (real space) in a forward direction from the HMD 100, inother words, in a direction of the visual field of the user wearing theimage display unit 20. The video cameras 61R and 61L capture an image ina range overlapping the visual field of the user or in the direction ofthe visual field of the user to perform imaging in a direction forvisual recognition of the user. In this embodiment, a width of an angleof view of the video cameras 61R and 61L is set to allow the videocameras 61R and 61L to capture the entire visual field of the user inwhich the user can have visual recognition through the rightlight-guiding plate 26 and the left light-guiding plate 28. An opticalsystem capable of appropriately setting the width of the angle of viewof the video cameras 61R and 61L may be provided.

Similarly to the video cameras 61R and 61L, the inward-facing camera 62is a digital camera equipped with an imaging element such as a CCD or aCMOS, an imaging lens, and the like. The inward-facing camera 62captures an image in an inward direction of the HMD 100, in other words,in a direction facing the user wearing the image display unit 20. Theinward-facing camera 62 of this embodiment includes an inward-facingcamera for capturing an image of the right eye of the user, and aninward-facing camera for capturing an image of the left eye of the user.In this embodiment, a width of the angle of view of the inward-facingcamera 62 is set to a range in which an image of the entire right eye orthe entire left eye of the user can be captured. The inward-facingcamera 62 is used to detect a position of the eyeballs of the user,particularly a position of the pupils, and to calculate a direction ofthe line-of-sight of the user from a position of the pupils of the eyes.Of course, the inward-facing camera 62 may be provided with an opticalsystem capable of appropriately setting a width of the angle of view,and may be used to read a facial expression of the user or the like bycapturing not only an image of the pupils of the user but also a largerregion.

The illuminance sensor 65 is provided at the end ER of the front frame27 and is disposed to receive outside light from the front of the userwearing the image display unit 20. The illuminance sensor 65 outputs adetection value corresponding to an amount of received light (intensityof received light). The LED indicator 67 is disposed at the end ER ofthe front frame 27. The LED indicator 67 is turned on during imagecapturing by the video cameras 61R and 61L to notify that the imaging isin progress.

The six-axis sensor 66 is an acceleration sensor and detects an amountof movement of the head of the user in X, Y, and Z directions (3 axes)and the inclination of the head of the user in the X, Y, and Zdirections (3 axes). With respect to the X, Y, and Z directions, the Zdirection is a direction along the gravitational direction, the Xdirection is a direction from the rear to the front of the user, and theY direction is a direction from the left to the right of the user. Inaddition, an inclination of the head is an angle around each axis(X-axis, Y-axis, and Z-axis) of the X, Y, and Z directions. An amount ofmovement and an angle of the head of the user from an initial positioncan be ascertained by combining signals from the six-axis sensor 66.

The image display unit 20 is coupled to the control device 70 via acoupling cable 40. The coupling cable 40 is pulled from the tip of theleft holding part 23 and is detachably coupled to a connector 77provided on the control device 70 via a relay connector 46. The couplingcable 40 includes a headset 30. The headset 30 includes a microphone 63,and a right ear bud 32 and a left ear bud 34 attached to the left andright ears of the user. The headset 30 is coupled to the relay connector46 and is integrated into the coupling cable 40.

When a signal from the control device 70 for displaying an image isoutput to the image display unit 20 via the coupling cable 40, the imagedisplay unit 20 forms an image using the right display unit 22 and theleft display unit 24. An optical configuration for helping the userrecognize an image will be described. FIG. 2 is a plan view illustratinga main part of a configuration of an optical system included in theimage display unit 20. For convenience of description, FIG. 2illustrates the right eye RE and left eye LE of a user. As illustratedin FIG. 2, the right display unit 22 and the left display unit 24 areconfigured to be symmetric on the right- and left-hand sides.

As a configuration to allow the right eye RE to visually recognize avirtual image, the right display unit 22 serving as a right imagedisplay unit includes an organic light emitting diode (OLED) unit 221and a right optical system 251. The OLED unit 221 emits imaging light.The right optical system 251 includes a lens group and the like andguides, to the right light-guiding plate 26, imaging light L emitted bythe OLED unit 221.

The OLED unit 221 includes an OLED panel 223 (which will be abbreviatedsimply as an OLED) and an OLED driving circuit (which will beabbreviated simply as an R-CPLD) 225 configured to drive the OLED 223.The OLED 223 is a self-luminous display panel including light-emittingelements configured to emit red (R), green (G), and blue (B) colorlight, respectively, using organic electro-luminescence. The OLED 223includes a plurality of pixels arranged in a matrix form, and each pixelincluding one R, G, and B elements as one unit.

The R-CPLD 225 selects and powers the light-emitting elements includedin the OLED 223 according to a signal transmitted from the controldevice 70 to cause the light-emitting elements to emit light. The R-CPLD225 is fixed onto a rear surface of the OLED 223, i.e., the back side ofa light-emitting surface by bonding or the like. The R-CPLD 225 mayinclude, for example, a semiconductor device configured to drive theOLED 223, and may be mounted onto a substrate fixed to the rear surfaceof the OLED 223. Note that the OLED 223 may adopt a configuration inwhich light-emitting elements that emit white light are disposed in amatrix form and are disposed over color filters corresponding to thecolors R, G, and B, respectively. In addition, an OLED 223 with a WRGBconfiguration including light-emitting elements configured to radiatewhite (W) light in addition to light-emitting elements configured toradiate R, G, and B light, respectively, may be adopted.

The right optical system 251 includes a collimating lens configured tocollimate the imaging light L emitted from the OLED 223 into a luminousflux in a parallel state. The imaging light L collimated by thecollimate lens into a luminous flux in a parallel state is incident onthe right light-guiding plate 26. On an optical path configured to guidelight inside the right light-guiding plate 26, a plurality of reflectivesurfaces configured to reflect the imaging light L are formed. Theimaging light L is reflected multiple times inside the rightlight-guiding plate 26 and then, is guided to the right eye RE side. Ahalf mirror 261 (reflective surface) positioned in front of the righteye RE is formed in the right light-guiding plate 26. The imaging lightL reflected by the half mirror 261 is emitted from the rightlight-guiding plate 26 to the right eye RE to form an image on theretina of the right eye RE to allow the user to visually recognize avirtual image.

As a configuration to allow the left eye LE to visually recognize avirtual image, the left display unit 24 serving as a left image displayunit includes an OLED unit 241 and a left optical system 252. The OLEDunit 241 emits imaging light. The left optical system 252 includes alens group and the like and guides, to the left light-guiding plate 28,imaging light L emitted by the OLED unit 241. The OLED unit 241 includesan OLED 243, and an L-CPLD 245 configured to drive the OLED 243. Detailsof each of the units are the same as those of the OLED unit 221, theOLED 223, and the R-CPLD 225. Details of the left optical system 252 arethe same as those of the right optical system 251.

According to the configuration described above, the HMD 100 can functionas a see-through display device. That is, the imaging light L reflectedby the half mirror 261 and outside light OL passing through the rightlight-guiding plate 26 are incident on the right eye RE of the user. Theimaging light L reflected by a half mirror 281 and outside light OLpassing through the left light-guiding plate 28 are incident on the lefteye LE of the user. In this manner, the HMD 100 allows the imaging lightL of the image processed inside and the outside light OL to be incidenton the eyes of the user in an overlapped manner. As a result, the usercan view an outside scene (real world) through the right light-guidingplate 26 and the left light-guiding plate 28 and also visually recognizea virtual image formed by the imaging light L overlapping the outsidescene. In other words, the image display unit 20 of HMD 100 allows theoutside scene to pass through the image display unit and causes the userto visually recognize the outside scene in addition to the virtualimage.

The half mirrors 261 and 281 reflect imaging light output by the rightdisplay unit 22 and the left display unit 24, respectively, and extractan image. In addition, the right optical system 251 and the rightlight-guiding plate 26 are also collectively referred to as a “rightlight-guiding unit”, and the left optical system 252 and the leftlight-guiding plate 28 are also collectively referred to as a “leftlight-guiding unit”. Configurations of the right light-guiding unit andthe left light-guiding unit are not limited to the example describedabove, and any configuration can be used as long as a virtual image canbe formed in front of the eyes of the user using imaging light. Forexample, diffraction gratings or translucent reflective films may beused for the right light-guiding unit and the left light-guiding unit.

A-2. Configuration of Control Device 70:

Next, a configuration of the control device 70 that outputs varioussignals to the image display unit 20 will be described. FIG. 3 is ablock diagram illustrating an internal configuration of the controldevice 70 and the image display unit 20. The control device 70 includes,in addition to the display 73 described above, a communication unit 75,a CPU 80, a touch panel driver 76, a display driver 78, an input/outputinterface (which will be abbreviated simply as an input/output I/Fbelow) 79, and the like. Note that driving power of the control device70 is supplied to each of the units from a battery which is notillustrated in the drawing.

The display 73 includes a display unit 71 that displays an image in fullcolor and a touch panel 72 that detects the position and strength of thetouch on the display unit 71 when a user touches the display unit 71with his or her fingertip or the like. The display unit 71 is driven bythe display driver 78 that receives a signal from the CPU 80. Inaddition, the touch panel 72 is coupled to the touch panel driver 76,receives a driving signal from the touch panel driver 76 to dynamicallydetect a touch position on the display 73, and outputs the detectedtouch position and the strength to the CPU 80 via the touch panel driver76.

The communication unit 75 communicates with a mobile terminal 110 andreceives a video signal including images and sound. Any communicationmethod such as Wi-Fi (registered trademark), BlueTooth (registeredtrademark), or the like may be adopted. In addition, the video signalmay be received from the mobile terminal 110 via a wire. Theinput/output I/F 79 may have a connector form conforming to theso-called Type-C standard and is capable of inputting and outputtingdata in serial communication.

The CPU 80 that controls each of the units includes a memory 85 andrealizes functions of an operating system (which will be abbreviatedsimply as an OS) 81, an input event detection unit 82, and the like byexecuting programs stored in the memory 85. The OS 81 used in thisembodiment has the same basic function as that of a general-purpose OSused in the mobile terminal 110 and the like. Differences from the OSare the expanded functions of capturing images of outside scenes usingthe video cameras 61R and 61L, detecting a line-of-sight using theinward-facing camera 62, displaying images on the display 73 along withthe image display unit 20, and the like. Thus, an application programcreated for the OS 81 can be executed by the control device 70 as is orwith a slight modification. Conceivable examples of such an applicationprogram include games, application programs that support various kindsof work, and the like. Such an application program will be referred toas a target app 83. In addition, in this embodiment, separate from thetarget app 83, a user interface support application program (which willbe simply referred to as a UI app below) 84 that provides various inputmethods can be executed concurrently with the target app 83.

The CPU 80 outputs the video received from the mobile terminal 110 viathe communication unit 75 to the image display unit 20 via theinput/output I/F 79 under control of the OS 81. In conjunction with suchinput and output of video signals, the CPU 80 handles the display 73 asan input unit, causes images such as buttons, keys, or fields necessaryfor input to be displayed on the display unit 71 via the display driver78, and inputs the position and strength of a touch of the user on thetouch panel 72 in accordance with the display via the touch panel driver76. The position and strength of the touch detected by the touch paneldriver 76 are input to the input event detection unit 82, collated withthe status of the user interface for input received from the UI app 84,interpreted by the OS 81, and output to the target app 83. The form ofthe user interface for input and the technique of input by the OS 81 andthe UI app 84 will be described in detail below.

The CPU 80 outputs the video input via the communication unit 75 to theimage display unit 20 via the input/output I/F 79 under control of theOS 81. The image display unit 20 is constituted broadly by a basic board35, an optical module board 36, and a camera module board 37 asillustrated at the lower part of FIG. 3. The basic board 35 is equippedwith an interface unit (which will be simply referred to as an I/F unit)91 that exchanges video signals with the input/output I/F 79 of thecontrol device 70, a HUB 92 that separates signals and mediates thesignals between the I/F unit 91 and other units, an MCU 94 that takes apart of the signals from the HUB 92 to operate, and a display bridge 93that processes video signals with a help of processing by the MCU 94 andoutputs the video signals to the optical module board 36.

Another signal line from the HUB 92 is coupled to the camera moduleboard 37 and is used to output video signals from the video cameras 61Rand 61L and the inward-facing camera 62 mounted on the camera moduleboard 37 to the control device 70 via the HUB 92 and the I/F unit 91.The CPU 80 can analyze videos from the video cameras 61R and 61L,recognize a product, or the like present in the visual field of theuser, and also can perform processing such as causing the image displayunit 20 to display provided information of the product. In addition, theCPU 80 can also analyze the video from the inward-facing camera 62 tospecify the direction of the line-of-sight of the user and performprocessing such as specifying the target object that the user is viewingin the outside scene captured by the video cameras 61R and 61L.

The optical module board 36 is equipped with an FPGA 95, and the R-CPLD225, the L-CPLD 245, and the six-axis sensor 66 that are describedabove. The FPGA 95 is coupled to the display bridge 93 of the basicboard 35, separates video signals received from the display bridge 93into video signals for the right and left eyes, and further converts thesignals into RGB signals. The R-CPLD 225 and the L-CPLD 245 drive theOLEDs 223 and 243 in accordance with the signals from the FPGA 95. Thesix-axis sensor 66 is coupled to the display bridge 93 on the basicboard 35 and outputs postures (on three axes) and accelerations of theimage display device 20 in each axial direction (on three axes).

The three axes indicating postures are for postures in the Z-axisdirection (top-bottom direction) that is the gravitational direction,the Y-axis direction (left-right direction) that is the direction thatis orthogonal to the Z-axis direction and extends from the right eye tothe left eye of the user wearing the image display unit 20 (FIG. 1), andthe X-axis direction (front-rear direction) that is the directionorthogonal to the Z-axis and the Y-axis. By nature, the head of a humaneasily takes four postures due to the structure of the skeleton, thefour postures including a right-side rotational posture in which thehead rotates to the right eye side approximately about the Z-axis (thearrow RT side in FIG. 1), a left-side rotational posture in which thehead likewise rotates to the left eye side (arrow LT side in FIG. 1), anupward rotational posture in which the head rotates upward (arrow UPside in FIG. 1), and a downward rotational posture in which the headrotates downward (arrow DW in FIG. 1), and thus the image display unit20 may be configured such that signals from the six-axis sensor 66 areprocessed on the image display unit 20 side and are output as the fourpostures. An acceleration is an acceleration in each of the X-, Y-, andZ-axis directions.

A-3. Aspect of Display and Input:

On the premise of the hardware described above, modes of display andinput performed by the HMD 100 will be described. FIG. 4 is a flowchartshowing a display processing routine executed by the control device 70.This processing begins by inputting power to the control device 70 andselecting a specific application program, that is, the set target app83, to instruct the control device to activate the app.

When this processing routine is activated, the control device 70 sendspower to the image display unit 20 via the coupling cable 40 to activatethe entire HMD 100 (step S100). Thereafter, the control device 70activates the UI app 84 before starting the target app 83 (step S105).The UI app 84 is an application program that supports input of data tovarious target apps 83 under instructions of the OS 81 as illustrated inFIG. 3. Because the target app 83 operates under control of the OS 81,if the UI app 84 is not activated, the UI app displays a button or afield for input on a screen that is controlled by itself, that is, ascreen displayed on the image display unit 20, and performs an operationof the button, input of text data input to the field, and the like viaan input mechanism provided by the OS 81. Examples of the inputmechanism include a mechanism in which a virtual button displayed on theimage display unit 20 is selected by detecting a line-of-sight using theinward-facing camera 62, detecting the line-of-sight being blocked by amovement of the eyelid movement, and pressing (determining) the selectedbutton, and a mechanism in which a sound input by the microphone 63 isrecognized and text data is input to the field selected by theline-of-sight.

These mechanisms are realized by invoking a function call provided bythe OS 81 on standard from the application program side. The OS 81 isset to provide various function calls dedicated to the HMD 100 to allowthe application program to display a specific button or field and acceptan input from the user while the UI app 84 is not activated. On theother hand, when the UI app 84 is activated in step S105, the OS 81operating on the control device 70 makes a change such that invoking ofthe function call provided on standard is passed to the UI app 84.

After completing the above preparation, processing by the target app 83designated to be activated is started. Thus, the processing from stepS110 which will be described below is performed by the target app 83.When the target app 83 starts processing, the video cameras 61R and 61Lare used to capture an image of an outside scene (step S110). Next,processing to recognize a target object from the captured outside sceneis performed (step S120). This is processing to determine whether apre-registered target object is present in the captured outside scene.The target app 83 activated in this embodiment is configured to supportwork of users, and if a product to work on or the like is within thevisual field, the target app 83 detects the product and performs supportprocessing which will be described below.

Next, it is determined whether there is a pre-registered target torecognize in the captured outside scene (step S125), and if there is notarget to recognize (step S125: “NO”), the processing returns to stepS100 to repeat the processing described above. If there is apre-registered target to recognize in the outside scene (step S125:“YES”), processing of preparing a material of the target to recognize isthen performed (step S130). The material is a manual, a workinstruction, or the like, of the product to work on.

Next, the control device 70 sets a standard posture (step S150). Thestandard posture is an initial posture made when the user works usingthe HMD 100. Normally, the posture made when detecting the target instep S120 is registered as a standard posture. The standard posture isset based on angles of the head of the user in the X, Y, and Z-axisdirections acquired from the six-axis sensor 66. A movement of the headof the user, which will be described below, is detected as a movementfrom this standard posture.

Although the standard posture is assumed to be defined as a posture madewhen the target is detected in this embodiment, the standard posture canbe variously defined in accordance with types of work, or the like. Aposture of the user is not limited to a posture of the user facing thefront, and in some cases, a posture of the user facing the right side,the left side, or upward or downward is conceivable as a standardposture. In addition, a sit-and-work state may be a standard posture,and a stand-and-work state may be a standard posture. Various methodscan be used to set a standard posture. One of the methods may beconfigured such that a “standard posture setting button” is displayed onthe display 73 of the control device 70 and the posture made when theuser is pressing the button may be registered as a “standard posture”. Astandard posture may be registered using voice recognition or the like,instead of a button. Furthermore, several postures may be registered inadvance as standard posture candidates, and one of them may be selectedas a standard posture. Furthermore, standard postures may be definedaccording to a work stand or a desk on which a user works, a cart or aworkpiece carried by a conveyor or a line, a tool or a jig operated byusers, and the like.

Alternatively, a SLAM technology in which a map of an environment inwhich a user is using the HMD 100 and the location of the user in theenvironment map are estimated from a large number of images obtained bycapturing the surroundings of the user by an external camera (notillustrated) moving the place around the user using the HMD 100 or bythe video cameras 61R and 61L provided on the HMD 100 may be used torecognize the location and the posture of the user in the useenvironment and defined a standard posture based on the location and theposture. Among locations and postures of the user in the use environmentrecognized using the SLAM technology, the location and the posture inwhich the user remained and worked most frequently or for a long timemay be set as a standard posture, or the location and posture taken atthe start of work may be set as a standard posture. Alternatively, astandard posture may be defined based on a location and a posture takenat another predetermined time.

Although the standard posture is assumed to be defined as a posture madewhen the target is detected in this embodiment, the standard posture canbe variously defined in accordance with types of work, or the like. Oneof the methods may be configured such that a “standard posture settingbutton” is displayed on the display 73 of the control device 70 and theposture made when the user is pressing the button may be registered as a“standard posture”. A standard posture may be registered using voicerecognition or the like, instead of a button. Furthermore, severalpostures may be registered in advance as standard posture candidates,and one of them may be selected as a standard posture. Furthermore,standard postures may be defined according to a work stand, a desk, or acarriage or a workpiece carried by a conveyor or a line on which userswork, a tool or a jig operated by users, and the like.

Furthermore, a SLAM technology in which a map of the environment inwhich a user is using the HMD 100 and the location of the user in theenvironment map are estimated from a large number of images ofperipheries of the user captured by an external camera (not illustrated)moving the place in which the user is using the HMD 100 or by the videocameras 61R and 61L provided on the HMD 100 may be used to recognize thelocation and the posture of the user in the use environment, and astandard posture may be defined based on the location and the posture.Among locations and postures of the user in the use environmentrecognized using the SLAM technology, the location and the posture inwhich the user stayed and made most frequently for a long time may beset as a standard posture, or the location and posture taken at thestart of work may be set as a standard posture. Alternatively, astandard posture may be defined based on a location and a posture takenat another predetermined time.

When the setting of the standard posture is completed, the initialdisplay processing is then performed (step S160). The initial displayprocessing is to perform preset initial display on the outside sceneviewed by the user through the image display unit 20. FIG. 5 is anexplanatory diagram illustrating various modes of display realized bythe target app 83. The screen SG shown at the center of FIG. 5 shows astate in which a user attempting to work is viewing a target object OBJon the desk. On the screen SG, a hand HD of the user is depicted asbeing in the visual field of the user. This state is the visual field ofthe user in a standard posture. At this moment, as initial display,arrows AM indicating the four upward, downward, left, and rightdirections are displayed on the screen SG. These arrows AM are imagesthat the control device 70 causes the image display unit 20 to display.The arrows AM indicate that there is some information in the directionsof the arrows. Because information is available in all of the fourdirections in this embodiment, the arrows AM are displayed in theupward, downward, left, and right directions, however, if there is noinformation in the left direction, arrows AM are displayed in only threedirections including upward, downward, and right directions. The initialdisplay may not be provided of course, and may be provided in adifferent display mode, such as part of the provided information isvisible, instead of using arrows.

Next, the control device 70 performs processing of acquiring themovement of the head based on information from the six-axis sensor 66provided in the image display unit 20 (step S170). Although the movementof the head can be in various forms, information created by combininginformation of the direction in which the head moves among the upward,downward, left, and right directions with the magnitude of theacceleration of the movement can be acquired. Here, as described usingFIG. 1 before, the upward, downward, left, and right directions are theupward direction UP in which the user raises the face (head), thedownward direction DW in which the user lowers the face, the left sideLT to which the user turns his or her face in the left direction, andthe right side RT to which the user turns his or her face in the rightdirection.

After acquiring the movement of the head, it is determined whether themovement satisfies a predetermined condition (step S175), and if thecondition is satisfied, display processing corresponding to eachcondition is performed (step S200). Details of the display processing(step S200) will be described below. If the condition is not satisfied(step S175: “NO”), the processing returns to step S160 to repeat theabove-described processing. On the other hand, when the condition issatisfied and the display processing (step S200) is performed, it isthen determined if the work is to be ended (step S185), and when thecontrol device 70 ends the target app 83 or the control device 70 isturned off, the processing proceeds to “END” to end the presentprocessing routine. If it is determined that the processing is not to beended, the processing returns to step S160 to repeat the above-describedprocessing.

Next, the processing of step S200 in FIG. 4, that is, the displayprocessing when each condition is satisfied, will be described usingFIG. 6. When the movement of the head satisfies the predeterminedcondition in step S175, the control device 70 performs the next displayprocessing under each condition. In the example illustrated in FIG. 6,there are four conditions for detecting a movement of the head.

1 Condition 1: When the Head Faces the Right Side

When the head faces the right side at a predetermined angle (here, 40degrees) or more and the acceleration of the head in the right directionRT at that time is higher than or equal to a predetermined thresholdvalue based on a signal from the six-axis sensor 66;

2 Condition 2: When the Head Faces the Left Side

When the head faces the left side at a predetermined angle (here, 40degrees) or more and the acceleration of the head in the left directionLT at that time is higher than or equal to a predetermined thresholdvalue based on a signal from the six-axis sensor 66;

3 Condition 3: When the Head Faces Upward

When the head faces upward at a predetermined angle (here, 15 degrees)or more and the acceleration of the head in the upward direction UP atthat time is higher than or equal to a predetermined threshold valuebased on a signal from the six-axis sensor 66; and

4 Condition 4: When the Head Faces Downward

When the head faces the downward at a predetermined angle (here, 15degrees) or more and the acceleration of the head in the downwarddirection DW at that time is higher than or equal to a predeterminedthreshold value based on a signal from the six-axis sensor 66.

The conditions include the condition that the acceleration at the timeof viewing in a corresponding direction is higher than or equal to apredetermined value, and thus if the acceleration is equal to or lowerthan a predetermined threshold value, that is, the user is slowlyrotating his or her head in any of the upward, downward, left, and rightdirections even though the user is turning his or her head at apredetermined angle or more in the upward, downward, left, and rightdirections, the conditions [1] to [4] are not satisfied. In this case,the screen SG illustrated at the center of FIG. 5 is displayed as is.This case may occur when the user searches for the target object OBJ inthe right-left direction, e.g., when attempting to take a tool on thedesk. The condition that the acceleration of the head is higher than orequal to the predetermined threshold value is provided to detect asituation in which the user intentionally moves his or her head, ratherthan trying to simply look around from a standard posture. Note thatthreshold values for determining accelerations in the left, right,upward, or downward directions may be different from each other for eachdirection or may be the same in the plurality of conditions. Similarly,an angle for determining the head turning in the left, right, upward, ordownward direction at a predetermined angle or more may also bedetermined for each direction.

These conditions are exclusive and are not satisfied at the same timebecause the directions of the head are different. Thus, when one of theconditions is satisfied, any display processing (steps S210 to S240)corresponding to the condition is executed. Each processing is asfollows.

1 When Condition 1 is Satisfied:

In this case, the user of the HMD 100 sees the right side of the targetobject OBJ that has been viewed in the standard posture, and thusright-side display processing (step S210) is executed. As a result, thetarget object OBJ deviates from the center of the visual field, andinformation DC1, which is one piece of prepared content, is displayed onthe image display unit 20 as illustrated in the screen RG of FIG. 5.Thus, the user can refer to the information DC1 displayed in the visualfield. In this embodiment, when the user looks to the right side quicklyin view from the standard posture, the information DC1 describing anoperation method and a handling method for the target object OBJ isdisplayed. The information DC1 is scrollable as indicated by a scrollbar displayed as auxiliary display in the screen. An operation of thescroll bar requires some kind of input processing. In this embodiment,as illustrated in FIG. 3, this input processing is performed using theUI app 84 and the input event detection unit 82. This processing will bedescribed below together.

2 When Condition 2 is Satisfied:

In this case, the user of the HMD 100 sees the left side of the targetobject OBJ that has been viewed in the standard posture, and thusleft-side display processing (step S220) is executed. As a result, thetarget object OBJ deviates from the center of the visual field, andinformation DC2, which is one piece of prepared content, is displayed onthe image display unit 20 as illustrated in the screen LG of FIG. 5.Thus, the user can refer to the information DC2 displayed in the visualfield. In this embodiment, when the user looks at the left side quicklyin view from the standard posture, various kinds of the information DC2on the target object OBJ are displayed. The information DC2 can bereferred to back and forth using page flipping buttons displayed asauxiliary display in the screen. An operation of the buttons requiressome kind of input processing similar to the scroll bar. This processingwill be described below together.

3 When Condition 3 is Satisfied:

In this case, the user of the HMD 100 sees upward of the target objectOBJ that has been viewed in the standard posture, and thus upwarddisplay processing (step S230) is executed. As a result, the targetobject OBJ deviates from the center of the visual field, and the screenUG displaying prepared options is displayed on the image display unit20. The screen UG includes display for assigning a relationship betweenthe direction of the head and the screen as auxiliary display. Usingthis screen UG, the user can set the display on the HMD 100. The settingof the display refers to what information or screen display is assignedin which direction when viewed in the standard posture. Also in thiscase, some kind of input processing is required, similarly to Conditions1 and 2.

4 When Condition 4 is Satisfied:

In this case, the user of the HMD 100 sees downward of the target objectOBJ that has been viewed in the standard posture, and thus downwarddisplay processing (step S240) is executed. As a result, the targetobject OBJ deviates from the center of the visual field, and the screenDG performing setting and input provided in advance is displayed on theimage display unit 20. The screen DG displays options to be selected, afield for text input, and the like as auxiliary display. The user canmake a setting change, input text, or the like, with reference to thescreen DG. Some input processing is required for setting changes andtext input. This processing will also be described below.

One of the display in each display processing described abovecorresponds to display of a first mode, and another display correspondsto display of a second mode. Further, in each display processing, astate displayed on the display 73 to receive user operations and inputscorresponds to an input mode. In a first embodiment, input in differentinput modes is enabled for each display processing corresponding to thefirst to the fourth conditions. It can be ascertained which input modeis to be used when the display of the display 73 is viewed, but this maybe notified to the user using sound or vibration.

The right-side and left-side display processing described above will bedescribed using FIG. 7. In the display processing, a display mode forreceiving an input operation on the display 73 and an input operation inan input mode specified in accordance with the display mode areimplemented. While the processing is actually performed by the UI app 84and the input event detection unit 82, the following descriptionsummarizes a series of processing performed by the control device 70. Inaddition, although the right-side display processing (step S210) and theleft-side display processing (step S220) are illustrated as separateprocessing in FIG. 6, both kinds of display processing are illustratedand described here in conjunction with FIG. 7 because they have similarprocessing content. In addition, because the display by the imagedisplay unit 20 and the display of the control device 70 by the display73 are presented in the processing illustrated in FIG. 7, the displayunits will be distinguished by referring to the image display unit 20 asa first display unit 20, and the display 73 as a second display unit 73.

When the processing illustrated in FIG. 7 is started, whether there is amaterial to be displayed is first determined (step S211). If a materialto be displayed is not ready, the processing proceeds to “NEXT” to endthe present processing routine without performing any processing.Normally, because a material to be displayed is prepared (step S130 inFIG. 4), the control device 70 then causes the first display unit (imagedisplay unit) 20 to display material 1 (in the case of the right-sidedisplay processing) or material 2 (in the case of the left-side displayprocessing) (step S212). Thereafter, the control device 70 causes thesecond display unit (display) 73 to display up and down arrows forscrolling (in the case of the right-side display processing) or left andright arrows for page flipping (in the case of the left-side displayprocessing) (step S213).

An example of the display of the second display unit 73 is illustratedin FIG. 8. Although the displays DC1 and DC2 corresponding to thematerials 1 and 2 are also displayed on the second display unit 73, theyneed not be readable materials, and may be dummy displays for visuallyrecognizing display positions of the materials corresponding to theactual materials 1 and 2 displayed on the first display unit 20. In theright-side display processing, a bar BR constituting a scroll bar SB andan up arrow SBU and a down arrow SBD are displayed on the right side ofthe dummy display DC1. On the other hand, in the left-side displayprocessing, a left arrow PP and a right arrow PF for page flipping aredisplayed on the lower side of the dummy display DC2. In other words, inthe cases of the right-side display processing and the left-side displayprocessing, the input modes are different.

After the display on the first display unit 20 (step S212) and thedisplay on the second display unit 73 (step S213), it is determinedwhether an input operation using the second display unit 73 has beenperformed (step S214). The second display unit 73 includes the touchpanel 72 overlaid on the display unit 71, and thus can receiveoperations from a user as described above. The specific processing isperformed by the input event detection unit 82. When the input eventdetection unit 82 analyzes a signal from the touch panel driver 76, thatis, data indicating what degree of strength and which part of the seconddisplay unit 73 with respect to a touch of the user and the UI app 84determines that the user has touched the location corresponding to anyof the arrows SBU and SBD constituting the scroll bar SB displayed onthe second display unit 73 and the arrows PP and PF for forward andbackward page flipping with a constant or greater intensity, the inputevent detection unit 82 outputs to the OS 81 the occurrence of the eventin which the user has operated any of the arrows set by the UI app 84.

Specifically, if it is determined that the down arrow SBD has beenoperated in the processing of step S214 in the right-side displayprocessing, scrolling-down is performed (step S215). The scrolling-downis processing to scroll the material 1 displayed on the first displayunit 20 in the downward direction. As a result, the material 1 displayedas the display DC1 (see screen RG in FIG. 5) on the first display unit20 is scrolled in the downward direction, and the portion that washidden until then becomes visible. When it is determined that the arrowPP for backward page flipping has been operated in the left-side displayprocessing, backward page flipping is performed (step S215). Thebackward page flipping is processing to display the previous page of thematerial 2 displayed on the first display unit 20. As a result, theprevious page of the material 2 displayed as the display DC2 (see thescreen LG in FIG. 5) on the first display unit 20 is displayed andvisible.

On the other hand, when it is determined that the up arrow SBU has beenoperated in the processing of step S214 in the right-side displayprocessing, scrolling-up is performed (step S216). The scrolling-up isprocessing for scrolling the material 1 displayed on the first displayunit 20 in the upward direction. As a result, the material 1 displayedon the first display unit 20 is scrolled in the upward direction, andthe portion that was hidden until then is visible. When it is determinedthat the arrow PF for forward page flipping has been operated in theleft-side display processing, forward page flipping is performed todisplay the next page of the material 2 (step S216). As a result, thenext page of the material 2 displayed on the first display unit 20 isdisplayed and visible.

After the processing (steps S215 and S216) or during a predeterminedperiod of time, when the input event detection unit 82 has not detectedan event, it is determined in the next step S217 whether the posture ofthe user has returned to the standard posture. When the user facing theright or left side has not returned his or her head to its originalposition, that is, the position directly opposite to the target objectOBJ on the desk, the processing returns to step S213 to repeat theprocessing of steps S213 to S217 described above. On the other hand, ifthe user returns his or her head to the standard posture, the processingin step S217 is determined as “YES”, and the control device 70 turns offthe display of the first display unit 20 and the second display unit 73(step S218), and goes to “NEXT” to temporarily end the displayprocessing routine.

As described above, if the user dos not return his or her face to thestandard posture, the display on the first display unit 20 and thedisplay and input on the second display unit 73 are continued, and thus,even when the user performs an input operation viewing the controldevice 70 placed below while the information DC1 and the DC 2 are beingdisplayed and the user is viewing the right or left side, the displayand the like on the first display unit 20 are maintained without change.In addition, it is not necessary to set turn-off of the display on thefirst display unit 20 or the second display unit 73 to be triggered bydetection of return to the standard posture, and the display may returnto initial display (step S160 in FIG. 4) when there is a provided buttonsuch as “return to display of standard posture” on the second displayunit 73 and an explicit input operation by the user.

When the display processing illustrated in FIG. 7 is ended by returningthe head to the standard posture, the control device 70 proceeds to thedetermination of whether the processing described above is to be ended(step S185 in FIG. 4), and if conditions such as those for whether toend the target app 83 or the like are not satisfied, the processingdescribed above is repeated from the initial display processing (stepS160).

According to the processing described above, information displayed onthe right side or the left side can be easily scrolled or subjected topage flipping, and thus information that is not displayed at one timecan be viewed. Note that, although information that is not displayed atone time on the first display unit 20 is shown by scrolling or pageflipping in this example, a range of visible information may be changedby changing an enlargement/reduction ratio or a display size of thecontent. Alternatively, the display position of the content and thedisplay range of the content may be changed. In addition, it is alsopossible to use the information being displayed, such as by making amark on the content, through a button operation on the second displayunit 73.

In this way, while repeating the processing of FIG. 4, if a movement ofthe head satisfies the condition, the display corresponding to thecondition and the input in the input mode are enabled. For example, ifthe movement of the head of the user satisfies Condition 4, the controldevice 70 performs the downward display processing (step S240) shown inFIG. 6. Details of this processing are shown in FIG. 9.

When the downward display processing is started, the control device 70causes the first display unit (image display unit) 20 to display ascreen for input (step S242). An example of the screen for input isillustrated in FIG. 10. In this example, option SL1 for setting 1,option SL2 for setting 2, and further field FD for inputting text aredisplayed. Setting 1 is an example in which three radio buttons aredisplayed as option SL1, and any radio button is exclusively selected.Setting 2 is an example in which three check boxes are displayed asoption SL2 and multiple selections are allowed.

Following the display on the first display unit 20, the control device70 causes the second display unit (display) 73 to display a trackpad ora keyboard (step S243). An example of this display is illustrated inFIG. 11. In the downward display processing, a trackpad TP1 is displayedon the top of the second display unit 73, and a keyboard KB1 isdisplayed below the trackpad. Originally, the display is prepared by theUI app 84 and realized by the OS 81 writing data to be displayed intothe display unit 71 via the display driver 78.

After the display on the first display unit 20 (step S242) and thedisplay on the second display unit 73 (step S243), it is determinedwhether an input operation using the second display unit 73 has beenperformed (step S244). The second display unit 73 includes the touchpanel 72 overlaid on the display unit 71, and thus can receiveoperations from the user as described above. Specific processing is asdescribed in the right-side display processing and the like, and when itis determined that the user has touched a location corresponding to thetrackpad TP1 or a key of the keyboard KB1 illustrated in FIG. 11 with aconstant or greater strength, the input event detection unit 82 regardsthe determination as the occurrence of an event set by the UI app 84, inwhich either the trackpad TP1 or the keyboard KB1 has been operated, andoutputs the event to the OS 81.

As a result, selection display processing (step S246) is performed whenit is determined that a finger FP of the user traces the surface of thetrackpad TP1 to the right and left sides, or input character displayprocessing (step S245) is performed when it is determined that the usertaps at the position of each key of the keyboard KB1 with the finger FP.The selection display processing is processing in which a cursor cc onoptions SL1 and SL2 on the screen DG displayed in the first display unit20 illustrated in FIG. 10 is moved in a direction of the finger FPtracing the surface of the track pad TP1 to allow the user to tap on thesurface of the trackpad TP1 with the finger FP and select the option atthe position at which the cursor CC is present. In addition, the inputcharacter display processing is processing of inputting characterscorresponding to keys operated on the keyboard KB1 illustrated in FIG.10 into the field FD on the screen DG displayed on the first displayunit 20 and displaying the characters.

After the processing (steps S245 and S246) or during a predeterminedperiod of time, when the input event detection unit 82 does not detectany event, it is determined in the next step S247 whether the posture ofthe user has returned to the standard posture. If the user facingdownward has not returned his or her head to the original position,i.e., the position directly opposite to the target object OBJ on thedesk, the processing then returns to step S243 to repeat the processingof steps S243 to S247 described above. On the other hand, if the userreturns his or her head to the standard posture, the processing in stepS247 is determined as “YES”, and the control device 70 turns off thedisplay of the first display unit 20 and the second display unit 73(step S248), and goes to “NEXT” to temporarily end the displayprocessing routine.

When the display processing illustrated in FIG. 9 is ended by returningthe head to the standard posture, the control device 70 proceeds to thedetermination of whether the processing described above is to be ended(step S185 in FIG. 4), and thus if the condition such as whether to endthe target app 83 or the like is not satisfied, the processing describedabove is repeated from the initial display processing (step S160). Forexample, if the movement of the head of the user satisfies Condition 4,the control device 70 performs the upward display processing (step S230)shown in FIG. 6. This processing is to setting display in the HMD 100.The setting of the display refers to what information or screen displayis assigned in which direction when viewed in the standard posture.Details of this processing are omitted in the description.

A-4. Actions and Effects of First Embodiment

According to the first embodiment described above, when a user using theHMD 100 performs processing such as repair, assembly, or the like on atarget object OBJ present in an outside scene that is visible throughthe image display unit 20, the user moves his or her head from astandard posture in which the user faces the target object OBJ to causeinformation supporting the processing or information necessary forsettings, and the like to be displayed at a position associated with thedirection and a magnitude of acceleration of the movement of the head.Moreover, in this case, various kinds of information, setting screens,and the like can be displayed on the display 73 of the control device 70in different display modes in the left, right, upward, and downwarddirections, and input in an input mode associated with the display modeis possible. Thus, the user can refer to desired information, or caninput a setting or text, or the like simply by moving his or her head ina predetermined direction from a standard posture at an accelerationhigher than or equal to a predetermined threshold value, As a result,processing such as repair, assembly, or the like for the target objectOBJ becomes easy.

Furthermore, because the input processing is performed on the display 73integrated with the touch panel 72 in the first embodiment, it is notnecessary to employ input processing using the image display unit 20,for example, input processing such as detecting a direction of theline-of-sight and shielding the line-of-sight by the eyelids. Because itis easy to set the input processing to be similar to normal processingusing the touch panel 72, for example, input processing with the mobileterminal 110, or the like, input operations can be simplified andintuitive. Moreover, in this embodiment, by changing the display of thedisplay unit 71 of the display 73, various input modes, such as thescroll bar SB, the buttons PP and PF in the form of an arrow for pageflipping, the options SL1 and SL2, the field FD for text input, and thelike can be realized.

Moreover, because such a variety of input modes are provided by UI app84 and the input event detection unit 82 controlled by the 0S81 at thelevel of the operating system for the environment in which the targetapp 83 operates, it is also easy to implant the target app 83 operatingon a mobile terminal or the like on which a similar operating system ismounted.

In addition, in the first embodiment, if the target object OBJ presentin the outside scene captured by the video cameras 61R and 61L providedin the image display unit 20 is a registered target object, the user canrefer to information prepared for the target object OBJ at any time.Thus, by simply having the image display unit 20 which can be displayedin a see-through manner, worn as eyeglasses, information related to awork target is easily accessible.

B. Second Embodiment

Next, a second embodiment will be described. An HMD 100 of the secondembodiment has a similar hardware configuration to that of the firstembodiment, and the processing performed by the control device 70 isdifferent. FIG. 12 is a flowchart showing a display processing routineexecuted by the control device 70 in the second embodiment. In thesecond embodiment, other processing is similar except that steps S110through S130 of the first embodiment are not included.

In the HMD 100 of the second embodiment, when the processing starts, thecontrol device 70 sends power to the image display unit 20 via thecoupling cable 40 to activate the entire HMD 100 (step S300).Thereafter, the control device 70 activates the UI app 84 beforestarting the target app 83 (step S305). Subsequently, similar to thefirst embodiment, the control device 70 sets a standard posture (stepS350).

When the standard posture is set, the initial display processing is thenperformed in the same manner as in the first embodiment (step S360), andprocessing is further performed to acquire the movement of the headbased on information from the six-axis sensor 66 provided in the imagedisplay unit 20 (step S370). The movement of the head can be determinedin the same manner as in the first embodiment, such as when the movementis a movement in a predetermined direction exceeding a predeterminedfirst threshold value value.

After acquiring the movement of the head, it is determined whether themovement satisfies a predetermined condition (step S375), and if thecondition is satisfied, display processing corresponding to eachcondition is performed (step S400). Details of the display processing(step S400) will be described later. If the condition is not satisfied(step S375: “NO”), the processing returns to step S360 to repeat theprocessing described above. On the other hand, when the condition issatisfied and the display processing (step S400) is performed, it isthen determined if the work is to be ended (step S385), and when thecontrol device 70 ends the target app 83 or the control device 70 isturned off, the processing proceeds to “END” to end the presentprocessing routine. If it is determined that the processing is not to beended, the processing returns to step S360 to repeat the above-describedprocessing.

Next, the processing of step S400 in FIG. 12, that is, the displayprocessing when each condition is satisfied, will be described usingFIG. 13. When the movement of the head satisfies the predeterminedcondition in step S375, the control device 70 performs the next displayprocessing under each condition. In the example illustrated in FIG. 13,there are three types of conditions for detecting a movement of the headand display processing applied to such cases.

1 Condition 1: When the Head Faces the Right Side

When it is determined based on a signal from the six-axis sensor 66 thatthe head faces the right side at a predetermined angle (here, 40degrees) or more from the standard posture, an application program forplaying back a dynamic image is activated as the target app 83, theimage display unit 20, which is the first display unit, displays thedynamic image while the display 73, which is the second display unit,displays a remote controller, and thereby input in an input mode usingthe remote controller is possible (step S410).

2 Condition 2: When the Head Faces the Left Side

When it is determined based on a signal from the six-axis sensor 66 thatthe head faces the left side at a predetermined angle (here, 40 degrees)or more from the standard posture, a program for game 1 is activated asthe target app 83, the image display unit 20, which is the first displayunit, displays a screen of the game 1 while the display 73, which is thesecond display unit, displays a gaming pad, and thereby input in aninput mode using the gaming pad is possible (step S420).

3 Condition 3: When the Head Faces Downward

When it is determined based on a signal from the six-axis sensor 66 thatthe head faces downward at a predetermined angle (here, 15 degrees) ormore from the standard posture, a program for selecting an applicationprogram is activated as the target app 83, the image display unit 20,which is the first display unit, displays an app selection screen whilethe display 73, which is the second display unit, displays a compositeinput pad, and thereby input in an input mode using the composite inputpad is possible (step S430).

After any of the above-described determination and display processing(steps S410 to S430) is performed, the processing proceeds to “NEXT” toend the processing routine.

The display of the second display unit 73 and the input mode in eachdisplay processing (steps S410 to S430) described above will bedescribed. FIG. 14A is a schematic diagram illustrating a remotecontroller displayed in the second display unit 73 under Condition 1.The remote controller is displayed with a playback button PL to instructplayback of a dynamic image displayed in the first display unit 20, astop button ST to instruct a stop, a fast-forward button FF to instructfast forward of the dynamic image, a rewind button FB to instructrewinding of the dynamic image, and the like. When the user touches anyof the buttons viewing the display of the remote controller of thesecond display unit 73, the input event detection unit 82 detects anoperation on the touch panel 72 via the touch panel driver 76,determines which button has been pressed, and outputs an event assignedto the button, i.e., an event such as start of playback, stop, fastforwarding, rewinding of a dynamic image, or the like to the target app83. As a result, the dynamic image displayed on the first display unit20 is played back, stopped, fast forwarded, or rewound.

In addition, FIG. 14B is a schematic diagram illustrating a gaming paddisplayed under condition 2. The gaming pad displays a cross key XC andfour selection buttons BG. When the user operates a cross key XC of thegaming pad displayed on the second display unit 73 or taps on any ofbuttons BG as necessary while viewing the game displayed on the firstdisplay unit 20, the input event detection unit 82 detects the operationof the touch panel 72 via the touch panel driver 76 and determines inwhich direction the cross key XC has been operated or determines whichof the buttons BG has been pressed, and instructs an event assigned tothe button or a movement of a target character, a weapon, or the like,in upward, downward, left, or right direction, or outputs an event suchas specification of an operation of a weapon to the target app (here,the game) 83. As a result, the character displayed in the first displaypart 20 moves or the weapon is manipulated.

In addition, FIG. 14C is a schematic diagram illustrating a compositeinput pad displayed under condition 3. A cross key XC and a trackpad TPare displayed in the composite input pad. When the user operates thecross key XC of the composite input pad displayed on the second displayunit 73 or taps or drags on the trackpad TP as necessary while viewing aselection screen for an application program displayed on the firstdisplay unit 20, the input event detection unit 82 detects the operationof the trackpad TP via the touch panel driver 76 and determines in whichdirection the cross key XC has been operated or identifies the movementof the finger on the trackpad TP, and instructs a movement of a cursoron a selected screen in upward, downward, left, or right direction,oroutputs an event such as selection of a desired application program tothe target app (here, a program for selecting the application program)83. As a result, an application program displayed in the first displayunit 20 is selected and, in some cases, activated.

Even in the second embodiment described above, content to be displayedis changed according to a direction and a magnitude of a movement of thehead of the user wearing the HMD 100 and an input method in an inputmode according to the displayed content is provided as in the firstembodiment. Thus, similar effects to those of the first embodiment, suchthat the user can view a screen in which his or her desired informationand the like are displayed due to the movement of the user and canperform input in an input mode suitable for the screen can be.

Although various input mechanisms such as a remote controller, a gamingpad, or a composite input pad are displayed as each input mode on thedisplay 73 as the second display unit of the control device 70 in thesecond embodiment, an input mechanism suitable for the input mode is notlimited thereto. For example, as illustrated in FIG. 14D, an input meanswith a hexagonal shaped button may be displayed on the display 73 toallow the user to manipulate each button. In this example, in additionto the buttons BT1 to BT4 which move the cursor displayed on the imagedisplay unit 20 as the first display unit in each of the upward,downward, left, and right directions, a button BT5 for confirmation,buttons BT6 and BT7 for getting the game forward and backward, and thelike may be displayed and selected. Further, such a hexagonal-shapedbutton may be arranged outside the buttons BT1 to 7. An input mode inwhich buttons having a shape of filling such planes (triangular shape,square shape, hexagonal shape, or a combination of multiple shapes) arearranged to provide many options is also possible.

Alternatively, as illustrated in FIG. 14E, an input mechanism using anumeric keypad used in mobile phones or the like can also be employed.In this example, the numeric keypad is displayed on the display 73, andwhen a location corresponding to each key is touched, a square-shapedcursor KS indicating that the key has been selected is displayed, andthus a number or alphabet can be input. Originally, each key may beflipped left, right, up, and down to selectively input a plurality oftypes of characters. Furthermore, in this example, because the entiredisplay region also functions as the trackpad TP, it is possible to usea cursor, a character, or the like displayed on the image display unit20 to move in any direction. Because the numeric keypad can be used toinput alphabets, Japanese Kana characters, and the like associated inadvance with the keys by touching the keys multiple times within apredetermined time, and it is also easy to input text with a mixture ofJapanese Kana and Chinese characters, in combination with JapaneseKana-Chinese character conversion.

Although several input modes have been described above, these inputmodes may be combined, or may be switched on the same display screen asrequired by the user. The input mode switching is performed by combiningthe direction in which the head of the user moves as a movement of thehead with a determination that the magnitude of the movement exceeds thethreshold value. When the magnitude of the movement is determined as anangle of the head, a threshold value angle can be arbitrarily set.Because a so-called discriminative visual field in which a person gazesan object for visual recognition is within the range of approximately 5degrees, for example, if an angle of the head exceeds the value, thehead may be determined to face the left or right direction.Alternatively, because an effective visual field in which a person canreceive information simply by eye movement is approximately 30 degreesin the left and right directions and approximately 20 degrees in thevertical direction, if the head moves by an angle exceeding the aboveangles, the user may be determined to have moved his/her head and havetries to see a different direction from the standard posture.Furthermore, in consideration of the fact that a stable field offixation in which a person can comfortably gaze an object only with amovement of the eyeballs and a motion of his or her head without movingthe trunk is 60 to 90 degrees in the left-right direction (widths differdepending on individuals) and 45 to 70 degrees in the up-down direction(widths differ depending on individuals), if a value exceeds the ranges,the person is determined to be viewing the object in a differentdirection using not only the movement of the head but also the entirebody and thus the display mode can be changed. Note that a magnitude ofthe movement is not limited to an angle, and may be determined by anangular velocity, various accelerations, or a combination thereof.

In the first and second embodiments, although the HMD 100 and thecontrol device 70 are coupled using a wire, they may be coupledwirelessly using Wi-Fi (registered trademark), BlueTooth (registeredtrademark), or the like. In addition, although, the HMD 100 enablesoutside scenes to be visually recognized as a see-through type in theabove-described embodiments, the image display unit 20 and the like maybe configured as a non-transparent display device, an outside scenecaptured by the video cameras 61R and 61L may be displayed on thenon-transparent display device, and thus a display device that enablesthe outside scene to be substantially visually recognized may beconfigured.

C. Other Embodiments

(1) The present disclosure can also be implemented in the followingaspects. One aspect is an aspect of a head-mounted display devicecapable of enabling an outside scene to be visually recognized, and thedisplay device may include an image display unit configured to displayan image; an input unit coupled to the display unit and enabling inputin at least a plurality of input modes; a setting unit configured toset, as a standard posture, a specific posture of the head of a userwearing the display device; a detection unit configured to detect amovement of the head of the user wearing the display device from thestandard posture; a display control unit configured to associate amovement of the head with a first mode and a second mode that isdifferent from the first mode, that are display modes of the imagedisplay unit, and cause the image display unit to perform display in thefirst mode when the detected movement of the head is a movement in apredetermined first direction and exceeds a predetermined firstthreshold value and perform display in the second mode when the movementis a movement in a second direction that is different from the firstdirection and exceeds a predetermined second threshold value; and aninput control unit configured to cause the input unit to accept theinput in an input mode associated in advance with the first mode or thesecond mode of the image display unit among the plurality of input modeswhen the image display unit performs display in the first mode or thesecond mode.

In this way, movements of the head are associated with the first modeand the second mode different from the first mode that are display modesof the image display unit, display is performed in the first mode or thesecond mode depending on a detected movement of the head, and whendisplay is performed in the first mode or the second mode, input in aninput mode associated in advance with the first mode or the second modeamong the plurality of input modes is possible. A movement of the headcan be determined based on a direction of the head and a parametercombined with the direction, such as an angle of the head, a motion orrotation speed of the head, and an acceleration thereof. Note that anangle, a velocity, an acceleration, and the like may be detected as ascalar quantity, may be determined in combination with a direction, ormay be detected as a vector quantity including a direction from thebeginning.

(2) In the display device, the display control unit may control theimage display unit in a mode in which visual recognition of the outsidescene is prioritized in the standard posture, and in the first mode andthe second mode, first information and second information associated inadvance with the modes may be displayed on the image display unit. Inthis way, visual recognition of the outside scene is prioritized in thestandard posture, and in the first and second modes, the firstinformation and the second information associated in advance with themodes can be viewed. Thus, information about a target object present inthe outside scene, information related to the outside scene, and thelike can be easily viewed.

(3) In the display device, the first direction may be a downwarddirection from the standard posture, the first threshold value may be athreshold value for detecting that at least one of a depression angle, aspeed, and an acceleration of the head is greater than or equal to apredetermined value, the display control unit may cause the imagedisplay unit to display, in the first mode, information for receiving adata input as the first information, and the input control unit maycause at least one of a numerical value, a character, and selection ofan option to be input by input in an input mode using the firstinformation. In this way, when the user faces downward from the standardposture, input can be performed in an input mode to input at least oneof a numerical value, a character, and selection of an option. Ofcourse, similar display and input in an input mode may be performed atan elevation angle with consciousness.

(4) In the display device, the second direction may be a right directionor a left direction from the standard posture, and the second thresholdvalue may be a threshold value for detecting that at least one of anangle, a speed, and an acceleration of the head is greater than or equalto a predetermined value, the display control unit may cause the imagedisplay unit to display, in the second mode, predetermined contentincluding at least one of a character, an image, and a video as thesecond information, and the input control unit may receive an input inan input mode for changing a display mode of the displayed content. Inthis way, the predetermined content including at least one of acharacter, an image, and a video can be displayed as the secondinformation in the right direction or the left direction rather than ina view range of the standard posture, and the display mode of thedisplayed content can be changed. Thus, desired content can be easilyreferred to.

(5) In the display device, the display mode of the content to be changedby the input control unit may be at least one of anenlargement/reduction ratio or a display size of the content, a displayposition of the content, a display range of the content, scrolling ofthe content, page flipping of the content, and marking on the content.In this way, the display mode of the displayed content can be easilychanged.

(6) In the display device, the display control unit may cause the imagedisplay unit to display association information for associating amovement of the head with the first mode and the second mode when themovement of the head is detected as a movement in an upward directionfrom the standard posture and at least one of an elevation angle, aspeed, and an acceleration of the head is greater than or equal to apredetermined value, and the input control unit may receive an input inan input mode using the association information and associate themovement of the head with the first mode and the second mode. In thisway, a relationship between the display of the first and second modesdisplayed separately from the standard posture and the movement of thehead can be freely combined in the display device. A display mode is notlimited to the first and second modes, and three or more modes may beset. In this case, in addition to the four display modes in the upward,downward, left, and right directions, the display locations may beextended to at least one of upper right, upper left, lower right, andlower left. Of course, the display location may be circular and displaymay be performed in a larger number of modes.

(7) In the display device, the detection unit may be a multi-axis sensorconfigured to detect an angle and an acceleration in the upward,downward, left, and right directions of the head, the setting unit mayset the standard posture based on a first detection value for the anglefrom the multi-axis sensor, and the display control unit may set each ofthe first threshold value and the second threshold value individuallyfor both the first detection value for the angle from the multi-axissensor and a second detection value for the acceleration. In this way, achange of the head from the standard posture can be detected with highaccuracy. Of course, such determination may be made only based on theangle or acceleration of the head. If the determination is made based onan acceleration, it is possible to easily distinguish a movement of thehead slowing turning to look around from a movement to see the displayof the first and second modes. In addition, the multi-axis sensor usedmay be a six-axis sensor, or may be a single-axis (for angle oracceleration) or a two-axis (for angle and acceleration) sensor, or acombination thereof, specialized only in the detected direction.

(8) In the display device, the first detection value may be a detectionvalue at which it is possible to distinguish a direction of a posture ofthe head among the upward, downward, left, and right directions whenviewed in the standard posture, and the first threshold value and thesecond threshold value may have different threshold values for the firstdetection value. In this way, the display in each direction can beindividually set.

(9) In the display device, the display control unit may cause the imagedisplay unit to display auxiliary display indicating the correspondinginput mode in the display of the standard posture, the first mode, andthe second mode. In this way, the user can easily ascertain which inputmode is realized in the first mode and the second mode.

(10) In the display device, the input control unit may notify that theinput is possible in one input mode among the plurality of input modesusing sound or vibration. In this way, the user can easily ascertainwhat the current input mode is.

(11) The present disclosure can also be implemented as a control methodfor a display device including a head-mounted image display unit capableof enabling an outside scene to be visually recognized. The controlmethod for the display device may be configured to set, as a standardposture, a specific posture of the head of a user wearing the displaydevice; to detect a movement of the head of the user wearing the displaydevice from the standard posture; to associate the movement of the headin advance with a first mode and a second mode that is different fromthe first mode, which are display modes of the image display unit and tocause the image display unit to perform display in the first mode whenthe detected movement of the head is a movement in a predetermined firstdirection and exceeds a predetermined first threshold value and performdisplay in the second mode when the movement is a movement in a seconddirection that is different from the first direction and exceeds apredetermined second threshold value; and to receive an input in aninput mode associated in advance with the first mode or the second modeof the image display unit among a plurality of input modes when theimage display unit performs display in the first mode or the secondmode. This configuration provides similar effects to those of thedisplay device of the present disclosure.

(12) In addition, the present disclosure can also be implemented as acomputer-executable program for controlling a display device providedwith a head-mounted image display unit capable of enabling an outsidescene to be visually recognized. This program realizes a settingfunction to set, as a standard posture, a specific posture of the headof a user wearing the display device; a detection function to detect amovement of the head of the user wearing the display device from thestandard posture; a display function to associate the movement of thehead with a first mode and a second mode that is different from thefirst mode, which are display modes of the image display unit and tocause the head-mounted image display unit to perform display in thefirst mode when the detected movement of the head is a movement in apredetermined first direction and exceeds a predetermined firstthreshold value and perform display in the second mode when the movementis a movement in a second direction that is different from the firstdirection and exceeds a predetermined second threshold value; and aninput function to receive an input in an input mode associated inadvance with the first mode or the second mode of the image display unitamong a plurality of input modes when the image display unit performsdisplay in the first mode or the second mode. When such a program isexecuted by a computer, similar effects to those of the display devicedescribed above can be exhibited.

(13) In each of the above-mentioned embodiments, part of theconfiguration realized by hardware may be replaced with software. Atleast part of the configuration realized by software may be realized bydiscrete circuit configurations. Further, when some or all of thefunctions of the present disclosure are realized by software, thesoftware (computer program) may be provided in a form stored in acomputer-readable recording medium. The “computer-readable recordingmedium” is not limited to a portable recording medium such as a flexibledisk or a CD-ROM, and includes various internal storage devices such asa RAM and a ROM and various external storage devices fixed to a computersuch as a hard disk. In other words, the “computer-readable recordingmedium” has a broad range of definition including any recording mediumcapable of storing data packets in a fixed manner rather than anon-transitory manner.

The present disclosure is not limited to the embodiments describedabove, and can be realized in various configurations without departingfrom the gist of the disclosure. For example, appropriate replacementsor combinations may be made to the technical features in the embodimentswhich correspond to the technical features in the modes described in theSummary to solve some or all of the problems described above or toachieve some or all of the effects described above. In addition, unlessthe technical features are described herein as essential technicalfeatures, such technical features may be deleted appropriately.

What is claimed is:
 1. A head-mounted display device configured to causean outside scene to be visually recognized, the display devicecomprising: an image display unit configured to display an image; aninput unit coupled to the display unit and configured to accept input inat least a plurality of input modes; a setting unit configured to set,as a standard posture, a specific posture of the head of a user wearingthe display device; a detection unit configured to detect a movement ofthe head of the user wearing the display device from the standardposture; a display control unit configured to cause the image displayunit to perform display in a first mode when the detected movement ofthe head is a movement in a predetermined first direction and exceeds apredetermined first threshold value and perform display in a second modewhen the movement is a movement in a second direction that is differentfrom the first direction and exceeds a predetermined second thresholdvalue, the movement of the head being associated with the first mode andthe second mode different from the first mode, that are display modes ofthe image display unit; and an input control unit configured to causethe input unit to accept the input in an input mode associated inadvance with the first mode or the second mode of the image display unitamong the plurality of input modes when the image display unit performsdisplay in the first mode or the second mode.
 2. The display deviceaccording to claim 1, wherein the display control unit, in the standardposture, controls the image display unit in a mode in which visualrecognition of the outside scene is prioritized, and in the first modeand the second mode, first information and second information associatedin advance with the modes are displayed on the image display unit. 3.The display device according to claim 2, wherein the first direction isa downward direction from the standard posture, the first thresholdvalue is a threshold value for detecting that at least one of adepression angle, a speed, and an acceleration of the head is greaterthan or equal to a predetermined value, and the display control unit, inthe first mode, causes the image display unit to display information forreceiving a data input as the first information, and the input controlunit causes at least one of a numerical value, a character, andselection of an option to be input by input in an input mode using thefirst information.
 4. The display device according to claim 2, whereinthe second direction is a right direction or a left direction from thestandard posture, and the second threshold value is a threshold valuefor detecting that at least one of an angle, a speed, and anacceleration of the head is greater than or equal to a predeterminedvalue, the display control unit, in the second mode, causes the imagedisplay unit to display predetermined content including at least one ofa character, an image, and a video as the second information, and theinput control unit receives an input in an input mode for changing adisplay mode of the displayed content.
 5. The display device accordingto claim 4, wherein the display mode of the content to be changed by theinput control unit is at least one of an enlargement/reduction ratio ora display size of the content, a display position of the content, adisplay range of the content, scrolling of the content, page flipping ofthe content, and marking on the content.
 6. The display device accordingto claim 2, wherein the display control unit causes the image displayunit to display association information for associating a movement ofthe head with the first mode and the second mode when the movement ofthe head is detected as a movement in an upward direction from thestandard posture and at least one of an elevation angle, a speed, and anacceleration of the head is greater than or equal to a predeterminedvalue, and the input control unit receives an input in an input modeusing the association information and associates the movement of thehead with the first mode and the second mode.
 7. The display deviceaccording to claim 1, wherein the detection unit is a multi-axis sensorconfigured to detect an angle and an acceleration in the upward,downward, left, and right directions of the head, the setting unit setsthe standard posture based on a first detection value for the angle fromthe multi-axis sensor, and the display control unit sets each of thefirst threshold value and the second threshold value individually forboth the first detection value for the angle from the multi-axis sensorand a second detection value for the acceleration.
 8. The display deviceaccording to claim 7, wherein the first detection value is a detectionvalue with which a direction of a posture of the head with respect tothe standard posture is distinguishable from among the upward, downward,left, and right directions, and the first threshold value and the secondthreshold value are different threshold values for the first detectionvalue.
 9. The display device according to claim 1, wherein the displaycontrol unit, during the display in the standard posture, the firstmode, and the second mode, causes the image display unit to displayauxiliary display indicating the corresponding input mode.
 10. Thedisplay device according to claim 1, wherein the input control unitnotifies using sound or vibration that the input is enabled in one inputmode among the plurality of input modes.
 11. A control method for adisplay device including a head-mounted image display unit configured tocause an outside scene to be visually recognized, the control methodcomprising: setting, as a standard posture, a specific posture of thehead of a user wearing the display device; detecting a movement of thehead of the user wearing the display device from the standard posture;associating the movement of the head in advance with a first mode and asecond mode different from the first mode that are display modes of theimage display unit; causing the image display unit to perform display inthe first mode when the detected movement of the head is a movement in apredetermined first direction and exceeds a predetermined firstthreshold value and perform display in the second mode when the movementis a movement in a second direction that is different from the firstdirection and exceeds a predetermined second threshold value; andreceiving an input in an input mode associated in advance with the firstmode or the second mode of the image display unit among a plurality ofinput modes when the image display unit performs display in the firstmode or the second mode.
 12. A non-transitory computer-readable storagemedium storing a computer-executable program for controlling a displaydevice including a head-mounted image display unit configured to causean outside scene to be visually recognized, the program achieving; asetting function to set, as a standard posture, a specific posture ofthe head of a user wearing the display device; a detection function todetect a movement of the head of the user wearing the display devicefrom the standard posture; a display function to cause the image displayunit to perform display in a first mode when the detected movement ofthe head is a movement in a predetermined first direction and exceeds apredetermined first threshold value and perform display in a second modewhen the movement is a movement in a second direction that is differentfrom the first direction and exceeds a predetermined second thresholdvalue, the movement of the head being associated with the first mode andthe second mode different from the first mode that are display modes ofthe image display unit; and an input function to receive an input in aninput mode associated in advance with the first mode or the second modeof the image display unit among a plurality of input modes when theimage display unit performs display in the first mode or the secondmode.